deletions | additions       diff --git a/Now_its_time_time.tex b/Now_its_time_time.tex  index 8dc3707..e7011b9 100644  --- a/Now_its_time_time.tex  +++ b/Now_its_time_time.tex 
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f = 2.51^{-m + c}  \label{eq:fluxcalib}  \end{equation}  where $c$ is a constant which we're going to determine. In astronomy, {\color{red}In practice,  this equation is usually rearranged to give: \begin{equation}  m = -2.5\log(f) + c.  \end{equation}  Derive this form. form.}  For two sources, the difference in their magnitudes is then proportional to the  ratio of their fluxes: